Real age of Christina Aguilera in Pokémon: The First Movie - Mewtwo Strikes Back
In the movie Pokémon: The First Movie - Mewtwo Strikes Back, Christina Aguilera was:
17 years old
That was the real age of the celebrity according to our calculation.
The calculation of the shown age took into account the first day of the year in which the movie Pokémon: The First Movie - Mewtwo Strikes Back was released:
January 1, 1998
And the day in which Christina Aguilera was born:December 18, 1980
Since movies usually don't take more than one year to be released since the beginning of the filming process, Christina Aguilera may have been one year younger or one year older than the shown age while some scenes of the movie were being filmed.